Method of gating castings



J. F. ,DIETER VMETHOD OF' CTATING CASTNGS .Fume H2, H923.

Filed July 18, 1921 mmf@ NM x

SWW/Wto?, lm z;

Patented dune l2, i923,

Moron4 Germany, or NEW Yoan, n.

Application filed July 18,

To all tti/0m it may concern.'

Be it known that I, JAMEs F. DIETER, a citizen of the United States,yresiding'at lflighland'?ark, in the State offNew Jersey, 5 have inventedcertain new and useful lmprovements in Method of @rating Castings, of"which the following is a specilication, reference bein had to theaccompanying drawing, forming a part hereof.

This invention relates to an improved method of gating castings of metalof low speciiic heat and particularly aluminum, and for convenience inthe specification and claim wherein reference will be made to aluminum,it will be understood that any other metal which presents similarproblems in casting is contemplated as an equivalent.

The properties of aluminum are such that it cannot be cast readilybecause of the rapid rate of cooling. In different parts of suchcastings it has heretofore been very diliicult to secure a uniform rateof cooling with the result that one part has often cooled more readilythan another and resulting stresses produce cracks or porosity. To meetthis condition makeshifts have been employed in the form of chillsembedded or rammed in the cores or molds and these chills have usuallybeen placed in the core boX at points where it was desirable toaccelerate the cooling to keep pace with cooling at other points. Forinstance, it has been the practise to place chills where the bulk ofmetal is greatest. The initial expense of making these chills, the laborof installing them and the cost of replacement has made their use veryundesirable and it is believed that unfavorable conditions in thecasting itself are apt to be created by the presence of chills.

ln the usual method of gating, risers are placed near they heaviestmetal parts and communicate with the mold. These risers serve thepurpose of supplying a head or pressure to the metal in the mold andalso a reserve to lill up the space left by contraction in cooling.Since the metal entering the risers flows from the mold and is the firstmetal poured, relatively speaking, it is natural that it should becomesomewhat chilled before reaching the risers and have a tendency tofreeze therein. rl'his condition, particularly in the casting ofaluminum, defeats one of the principal purposes of the e @eresmas METHODor serine cnsrrrves.

metal in the risers since it doesnot constitute a hot and effective'reserve.

ln accordance with the improved method chills are' veliminatedl and yetsuch condi-l tions are setup as will insure a uniform coolingthroughoutthe mold', all parts ot the casting been maintainedV at a sutlic-ienthigh temperature, during the cooling, by the hot metal within therisers. To accomplish this the risers are gated in the runners. Themetal is fed in uniformly through the pour- .ing basin and passesthrough the runners to the mold. The risers are gated in the runners sothat the metal ultimately held in reserve therein is the last metalpoured and hence the hottest. This hot metal effectively in maintainingthe temperature throughout the casting so that it will be caused to cooluniformly. There is illustrated in the accompanying drawing in somewhatdiagrammatic form a. gate embodying the invention.

ln the drawing- Figure l is a view in plan of a ask showing the risersinto the runners.

Figure 2 is a view in vertical section through the flask shown in Figure1 and taken along the planes indicated by the broken lines 2 2 of Figurel and looking in the direction of the arrows.

As the description proceeds it will be evident that not only is theinvention not limited tothe character of the metal employed in castingbut, further, is not limited to the type of casting or flask. Variationsin the form and disposition of the pouring basins, runners and riserswill suggest themselves to one skilled in the foundry art and be adaptedto prevailing conditions.

The flask a is shown as including a mold for any suitable casting. Thepouring basins I), two in number, have communicating therewith therunners c through which the metal flows to the mold and in these runnersare gated risers l in such number and posil large extent, the verypurpose of the risers since' the metal therein has not been in acondition to supplya head or pressure and '.ill up the space left bycontraction in cooling. Of course With metals,lik e aluminum,

of 10W specic heat the eect has been aci centuated to a, point Wherefreezing has `0ccurred.

In accordance with `the present invention the method ofgating is suchthat'contrary conditions vvare realized. The metal flowsl freely alongthe runners into the mold and f. sure uniform contraction Whilecontinuously Leccese 1N o chills are necessary and yet,.in practise,

better castings have `been secured than be# fore . I claim as myinvention: l -K `The herein described method of casting comprisingforming a riser in communication With the Arunner,V and between thepouring basin and' the mould properfwhereby the riser fills With .thelast poured metaL, Which metal feeds into, and exerts pressure on` themetal in the mould duringthe cooling thereof. c This specificationsigned this ninth day of July, A. D. 1921.

JAMES E DIETER.l

